Flexible ASIL D isolated gate driver
STMicroelectronics has launched a 1200V isolated gate driver for SiC MOSFETs and IGBTs that is qualified to the ASIL D safety level.
The STGAP4S can control inverters of different power ratings via programmable protections with diagnostics that allow ISO 26262 ASIL D qualification with an integrated analog-digital converter (ADC) and flyback controller.
The flexibility comes from the output circuit that allows connecting the high-voltage power stage to an external MOSFET’s push-pull buffer to scale the gate-current capability. The driver can generate up to tens of amperes of gate-drive current with very small MOSFETs and handles a maximum operating voltage of 1200V.
The diagnostics include self-checks to verify the integrity of connections, the gate-drive voltages, and correct operation of internal circuitry such as the desaturation and over-current detection. The host system can read the diagnostic-status register through the IC’s SPI port. In addition, two diagnostic pins provide hardware-detectable indications of fault status.
With protections including active Miller clamping, under-voltage and over-voltage lockout (UVLO, OVLO), as well as desaturation, overcurrent, and over-temperature detection, the STGAP4S enables robust and rugged designs that meet stringent reliability demands. The device has configurable parameters, including protection thresholds, deadtime, deglitch filtering, programmed through the SPI, giving extensive design flexibility.
The STGAP4S also integrates a fully protected flyback controller. This can be optionally used to generate the supplies of the high-voltage section for the positive and negative gate-driving signals for fast, efficient switching of SiC MOSFETs. The galvanic barrier provides 6.4kV of isolation between the low-side circuitry and the high-side sections.
The EVALSTGAP4S evaluation board includes two STGAP4S drivers to help complete evaluation of their features in a half-bridge application. The design lets users easily connect more boards together to evaluate more complex topologies such as a three-phase inverter.
The STGAP4S is in production now, in a SO-36W wide-body dual-inline package, priced from $4.66 for orders of 1000 units.
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